1; RUN: opt -passes=bpf-preserve-static-offset -mtriple=bpf-pc-linux -S -o - %s | FileCheck %s 2; 3; Check that bpf-preserve-static-offset folds GEP chains that end by 4; getelementptr.and.load. 5; 6; Source (modified by hand): 7; #define __ctx __attribute__((preserve_static_offset)) 8; 9; struct bar { 10; int aa; 11; int bb; 12; }; 13; 14; struct foo { 15; int a; 16; struct bar b; 17; } __ctx; 18; 19; extern void consume(int); 20; 21; void bar(struct foo *p) { 22; consume(p->b.bb); 23; } 24; 25; Compilation flag: 26; clang -cc1 -O2 -triple bpf -S -emit-llvm -disable-llvm-passes -o - \ 27; | opt -passes=function(sroa) -S -o - 28; 29; And modified to fold last getelementptr/load as a single 30; getelementptr.and.load. 31 32%struct.foo = type { i32, %struct.bar } 33%struct.bar = type { i32, i32 } 34 35; Function Attrs: nounwind 36define dso_local void @bar(ptr noundef %p) #0 { 37entry: 38 %0 = call ptr @llvm.preserve.static.offset(ptr %p) 39 %b = getelementptr inbounds %struct.foo, ptr %0, i32 0, i32 1 40 %bb1 = call i32 (ptr, i1, i8, i8, i8, i1, ...) 41 @llvm.bpf.getelementptr.and.load.i32 42 (ptr readonly elementtype(%struct.bar) %b, 43 i1 false, i8 0, i8 1, i8 2, i1 true, i32 immarg 0, i32 immarg 1) 44 #4, !tbaa !2 45 call void @consume(i32 noundef %bb1) 46 ret void 47} 48 49; CHECK: define dso_local void @bar(ptr noundef %[[p:.*]]) 50; CHECK: %[[bb1:.*]] = call i32 (ptr, i1, i8, i8, i8, i1, ...) 51; CHECK-SAME: @llvm.bpf.getelementptr.and.load.i32 52; CHECK-SAME: (ptr readonly elementtype(%struct.foo) %[[p]], 53; CHECK-SAME: i1 false, i8 0, i8 1, i8 2, i1 true, i32 immarg 0, i32 immarg 1, i32 immarg 1) 54; CHECK-SAME: #[[v2:.*]], !tbaa 55; CHECK-NEXT: call void @consume(i32 noundef %[[bb1]]) 56; CHECK: attributes #[[v2]] = { memory(argmem: read) } 57 58declare void @consume(i32 noundef) #1 59 60; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none) 61declare ptr @llvm.preserve.static.offset(ptr readnone) #2 62 63; Function Attrs: nocallback nofree nounwind willreturn 64declare i32 @llvm.bpf.getelementptr.and.load.i32(ptr nocapture, i1 immarg, i8 immarg, i8 immarg, i8 immarg, i1 immarg, ...) #3 65 66attributes #0 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" } 67attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" } 68attributes #2 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) } 69attributes #3 = { nocallback nofree nounwind willreturn } 70attributes #4 = { memory(argmem: read) } 71 72!llvm.module.flags = !{!0} 73!llvm.ident = !{!1} 74 75!0 = !{i32 1, !"wchar_size", i32 4} 76!1 = !{!"clang"} 77!2 = !{!3, !4, i64 8} 78!3 = !{!"foo", !4, i64 0, !7, i64 4} 79!4 = !{!"int", !5, i64 0} 80!5 = !{!"omnipotent char", !6, i64 0} 81!6 = !{!"Simple C/C++ TBAA"} 82!7 = !{!"bar", !4, i64 0, !4, i64 4} 83